Manual transmission vehicles are equipped with a clutch safety switch that is installed on the vehicle’s pedal mechanism. The switch is designed to prevent the vehicle from starting when the clutch pedal is not being pressed to prevent any sort of unintentional starting of the engine with the transmission in gear, as this will cause the vehicle to lunge forward and can be a potential safety hazard. When the clutch pedal is depressed, the clutch safety switch is closed and power is allowed into the vehicle’s ignition circuit so that the vehicle can be started when the key is turned. When the clutch safety switch fails, it can lead to issues starting the vehicle, and possibly even safety concerns. Usually a problematic clutch safety switch will produce a few symptoms that can alert the driver of a potential problem that needs to be serviced.
1. Vehicle does not start
One of the first symptoms commonly associated with a bad or failing clutch master safety switch is a vehicle that does not start. The clutch safety switch is designed to close and provide electricity when the pedal is depressed. However, if the switch fails, it will not be able to provide power for the starting circuit. This will lead to a vehicle that does not start when the key is turned, even if the pedal is depressed.
2. Starts while in gear
Another symptom of a problem with the clutch safety switch is a vehicle that starts while the transmission is in gear. If the clutch safety switch shorts internally, it can cause power to flow to the starting circuit if the pedal is not depressed, which will allow the vehicle to be started without stepping on the pedal and disengaging the clutch. This is a problem, as starting the engine of a manual transmission vehicle while the transmission is in gear may cause the vehicle to unexpectedly lunge forward, which could be a potential safety hazard.
3. Check Engine Light comes on
An illuminated Check Engine Light is another symptom of a problem with bad or failing clutch safety switch. Some vehicles will have their clutch safety switch circuit wired into the computer, and if a problem with the circuit or signal is detected, it will set off the Check Engine Light. A Check Engine Light can also be activated by a variety of other problems, so having the computer scanned for trouble codes is recommended.
A clutch safety switch is a simple but important safety feature installed on virtually all vehicles equipped with manual transmissions. Any problems with it can lead to issues with starting the vehicle, or can create potential safety concerns. For this reason, if you suspect that your vehicle is displaying any of the symptoms above, or you suspect your clutch safety switch may be having an issue, have the clutch inspected by a professional technician, such as one from YourMechanic, to determine if a clutch safety switch replacement is needed.
This article originally appeared on YourMechanic.com as Symptoms of a Bad or Failing Clutch Safety Switch and was authored by Ed Ruelas.